The Ministry of Construction has announced punitive measures against several contractors responsible for a tunnel collapse at a hydropower project last year that trapped a dozen of workers for four days.

Le Dinh Thang, chief supervision consultant and several engineers supervising the relevant package will be suspended for a year.

Underground Works Construction JSC, which was responsible for digging and reinforcing the tunnel, has been banned from the project. It cannot take up a major construction job at other projects for six months.

Site manager Nguyen Ngoc Ben and his deputy Nguyen Xuan Thanh will be suspended for a year.

Earlier, the project investor, Long Hoi Electricity Construction and Investment JSC and five contractors were fined a total of VND325 million (US$14,600).

The collapse happened on December 16, 2014 at the hydropower plant in Lam Dong Province's Lac Duong District. A section of the plant's tunnel caved in 500 meters from its entrance at about 7 a.m.

Twelve workers, including one woman, were stuck inside the tunnel after the incident. They were brought to safety four days later.

The tunnel was being built to bring water from a dam to the hydropower plant.

The project investor later said the accident was caused by rotten ceiling beams and weeks of incessant rain.